Block copolymer of a polyaminotriazole and an aromatic polyamide, and method of preparing same



United t s Paten mi 3,021,299 Patented Feb. 13, 1962 BLOCK COPOLYMER OF A POLYAMINOTRIA- ZOLE AND AN AROMATIC POLYAIVIIDE, AND METHOD OF PREPARING SAME William L. Evers, Summit, NJ., assignor to Celanese Corporation of America, New York, N.Y., a corporation of Delaware No Drawing. Filed Jan. 30, 1959, Ser. No. 790,056

10 Claims. (Cl. 20-42) This invention relates to polymeric materials and more particularly to polymeric materials which are especially suitable for the formation of filaments.

In synthetic fibers for textile use it is usually desirable to have certain properties such as high tenacity, high melting point and ease of dyeing. It is also often desirable to have stiifness in a fiber so that fabrics woven therefrom will be able to retain their shape or take a crease.

It is an object of this invention to provide new polymeric materials which are capable of producing fibers having an excellent balance of properties, especially including stiffness. Other objects will appear hereinafter.

The objects of this invention are achieved by preparing a block copolymer of a polyaminotriazole and a polyamide, said polyamide having the nitrogen atoms of its amide groups linked to aromatic nuclei in the chain by attachment of said nitrogen atoms to carbon atoms, all of whose valences are attached to atoms of the group consisting of carbon and hydrogen.

The block copolymers of this invention are prepared by heating a mixture of a polyaminotriazole with an amine-terminated polyamide, said polyamide having the nitrogen atoms of its amide groups linked to aromatic' iuclei in the chain by attachment of said nitrogen atoms carbon atoms, all of whose other valences are satisfied 3y atoms of the group consisting of carbon and hydrogen.

Polyaminotriazoles are suitably prepared by heating a nixture of a dihydrazide of a dicarboxylic acid with aqueaus hydrazine hydrate. For a particular dihydrazide, the nolecular weight of the product will depend upon the :emperature of the reaction, the proportion of water and he duration of the reaction. Higher temperatures, lower :roportions of water and longer reaction periods are conlucive to higher molecular weights.

Polyamides suitable for use in this invention may be arepared by heating the salt of a dicarboxylic acid and l diprimary aromatic amine in the presence of an excess )f the amine. Methods for preparing amine-terminated iolyamides of predetermined molecular weight are well mown to those skilled in the art. In general, the molecllar weight will be a function of the purity of the relctants, the quantity of diamine used as stabilizer, the legree of completeness of removal of the water of reiction, and the temperature and duration of the reaction. [he molecular weight is controlled most conveniently and nost satisfactorily by means of the quantity of stabilizer ised.

In general, it is preferred that the polyaminotriazole lave a chain length of at least 20 monomeric units.

When the polyaminotriazoles are prepared by the retction of the dihydrazide and aqueous hydrazine, the pre- Ferred conditions for obtaining a product of the molecular veight specified above include a temperature between ibout 190 and 230 C., an amount of hydrazine between about 5 and 10 percent by weight, based on the weight of the dihydrazide, an amount of Water between about 10 and 30 percent, based on the weight of the dihydrazide and a reaction period between about 5 and 15 hours.

The preferred class of polyaminotriazoles are those having structural units of the formula -(0H,)..O C-

wherein n is an integer from 6 to 12. They are prepared as described above, utilizing as reactants the dihydrazides of dialkanoic acids having from 8 to 14 carbon atoms. Among the preferred dihydrazides are sebacic dihydrazide, azelaic dihydrazide, suberic dihydrazide, adipic dihydrazide, methyl adipic dihydrazide, decanedioic dihydrazide and undecanedioic dihydrazide.

Other polyaminotriazoles which may be used contain structural units of the formula wherein R is a divalent organic radical free from reactive groups and having two terminal carbon atoms through which it is joined to the triazole rings. In addition to the preferred class of polyaminotriazoles described above,

other polyaminotriazoles having the structure describedimmediately above may be prepared from the dihydrazides of acids such as the following:

Isophthalic acid Terephthalic acid Phenylene diacetic acids Phenylene diproprionic acids Phenylene dibutyric acids p,p'-Dicarboxy-1,5-diphenoxypentane p,p'-Dicarboxy-l,4-diphenoxybutane p,p'-Dicarboxy-diphenoxymethane p-Carboxy-S-phenoxymethyl pyromucic acid Thio bis oenanthic acid Thio bis caproic acid Sulfone his caproic acid Thio bis valeric acid Sulfone bis valeric acid Thio bis propionic acid Sulfone bis propionic acid Thio bis butyric acid Sulfone bis butyric acid Thio bis acetic acid Sulfone bis acetic acid p,p-Dicarboxy diphenyl 1,4-dicarboxynaphthalene Pinic acid Norpinic acid Homopinic acid A suitable class of polyamides are those having the .-wherein R is a divalent organic radical and R; isa divalent organic radical having terminal carbon atoms which are linked only to carbon atoms or hydrogen atoms and having an aromatic nucleus and where n is an integer representing the degree of polymerization.

Polyamides of the structure described above are generally prepared by the reaction of a dicarboxylic acid with a predetermined excess of a diprimary aromatic amine to yield a polymer of desired molecular weight. Among the suitable diprimary aromatic amines which may be used are m-xylylene diamine, p-xylylene diamine, bis-13- aminoethyl benzene, bis-aminomethyl benzene, bis-,B aminoethyl durene, bis-aminomethyl durene, p,p-diaminodiphenyl, p,p'-diaminomethyldiphenyl, p,p'-diaminoethyldiphenyl, 1,4-diaminonaphthalene, 1,4-diaminomethylnaphthalene; 1,4-diaminoethylnaphthalene, 1,6-diaminonaphthalene, l,6-diaminomethylnaphthalene and 1,6-diarninoethylnaphthalene'.

Among the suitable dicarboxylic acids which may be used are the dialkanoic acids, such as adipic, pimelic and suberic and aromatic acids such as isophthalic. The preferred dicarboxylic acids are the dialkanoic acids having from 6 to 10 carbon atoms.

In general, it is preferred that the polyamides have a molecular weight at least as high as that of the polyaminotriazoles. Polyamides of such molecular Weights are preferably prepared by reacting the diamine-dicarboxiyic acid salt with excess diamine under conditions well e n in t n Polyaminotriazoles, suitable for use in accordance with this invention may be prepared in other ways, as for example by the reaction of one mole of a dicarboxylic acid with more than 2 moles of aqueous hydrazine. v 4

'Polyainides having the nitrogen atoms of their amide groups linked to aromatic nuclei in the chain by being attached to carbon atoms, all of whose other valences are satisfied by carbon or hydrogen atoms may also be preparedb'y the =autocondensation of an aromatic amino-acid, including a treatment to change the carboxylic acid end of the polymer to ai'r amine end. For example, m-aminomethylbenzoic acid'may be condensed with itself, in the presence of about l mole percent of m-xylylene diamine to produce an amine-terminated polyamide.

The copolymers of this invention are prepared by link ing the polyaminotriazole to the 'amine-terminated'polyamide. Polyaminotriazoles, prepared as described above, have hydrazide end groups which link to the amine end groups of the polyamide.

The reaction is generally carried out by heating a mixture of the prepolymers. The prepolymers may be intimately mixed in pulverized state and heated to a temperature between about 5 and 15 C. above the melting point of the higher melting component, or the prepolymers may be dissolved in a common high boiling solvent and heated to reflux temperature.

The prepolymers are preferably'blended in such proportions that there are more moles of the polyaminotn'azole prepolymer in the reaction Zone. The polyaminotriazole prepolymer is capable of reacting with itself to reduce the number of moles present during reaction. The polyamide being stabilized cannot react with itself but only with the polyaminotriazole prepolymer. Preferably between about 0.4 and 0.8 mole of polyamide prep-olymer are used for each 1 mole of polyaminotriazole.

When the materials are heated in bulk, they are preferably heated under an inert gas, such as nitrogen. The reaction period is preferably between about 3 0 and 120 minutes.

When the materials are heated in solution, a solvent is selected which can maintain a relatively high solids concentration, such as between about 25% and 60% by weight, based on the entire weight of the solution. Among the suitable solvents are m-cresol and o-phenylphenol. The solution is maintained at reflux temperature for a period between about 12 and-4'8hours 4 The preparation of the prepolymers and their combination is as follows:-

EXAMPLE I Preparation of prepolymer of polyamz'notriazole of sebacic acid Melting point=258 C. Inherent viscosity=0.33 (measured in 0.2% by weight of solution in m-cres'ol at 25 C.).

EXAMPLE 11 Preparation of prepolymer of m-iylylenediamine adipate 60.0 .g. of m-xylylenediammonium adipate salt, 0.4 ml. of m-xylylenediamine in 5 ml. of water were charged into a'glass'lined pipe autoclave. The autoclave was equipped with a pressure gauge and two valves that enabled the system to be kept under pressure or evacuated.

The autoclave was cleared of oxygen by flushing five times with nitrogen. The pressure was then set at 65 lbs. of nitrogen and the autoclave closed and placed in an oil bath at 240 C. After one hour at 240 C. under autog enous pressure the temperature was raised rapidly to 275 C. and held at this level for 2 hours. The pressure was slowly reduced to atmospheric andth'e autoclave heated an additional 3 hours. The resulting white, tough, opaque polymer had the following constants:

Melting point=240242 C. Inherent viscosity=0.54 (measured as above).

EXAMPLE III Preparation of prepolymer of p-xylylenediamine sebacate 8 g. of p-xylylenediammonium salt and 0.25 g. of pxylylene diamine were charged intoa glass lined pipe autoclave. The autoclave was cleared of oxygen by flushing three times with nitrogen. The autoclave was immersed in an oil bath for one hour with the pressure permitted to rise to 65 p.s.i.g. The temperature was then raised to 290 C. over a period of 15 minutes and maintained at that level for an additional hour at a pressure permitted to rise to p.s.i.g. The pressure Was slowly released over a period of twenty minutes and the temperature was maintained at 290 at atmospheric pressure for an additional two hours. Theresulting'creamy-white polymer 7 had the following constants:

Melting point=275-280 C. Inherent viscosity=0.34 (measured as above);

EXAMPLE IV Preparation of block copolyamides Block copolymers were prepared by two difierent methods as described below:

(a) Bulk method.The prepolymers were finely pulverized and intimately mixed in a glass tube that had a nitrogen inlet tube and could be evacuated.

The tube containing the two prepolymers was immersed in an oil bath at 260-270 C. for 10 min. at atmospheric pressure under nitrogen, followed by heating for 1 hour at 4.0 mm. Hg pressure under nitrogen. The product was then cooled and examined.

(b) Solvent p0lymerizati0n.The two prepolymers were dissolved in m-cresol and brought to a reflux under nitrogen. The solution ocntained about 50-60% solids and was refluxedabout 24 hours.' After cooling; the solu;

tion was-poured into "acetone to precipitate thepolyniei" 5 and washed thoroughly with hot acetone until free of m-cresol. The results of the various trials are as follows:

I Measured in 0.2 wt% solution of m-cresol at 25 C.

b MXD-G indicates the prepolyrner prepared from m-xylylene diammonium adipate according to Example 11.

v PAT indicates the prepolymer prepared from sebacio dihydrazide according to Example I.

d PXD-lt) indicates the prepolyrner prepared from p-xylylene diammonium sebacate according to Example 111.

All of the above block copolymers were fiber producing. The polymer produced from the prepolymers of Examples 1 and II by method (a) produced evceptionally tough fibers.

It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of my invention.

Having described my invention, what I desire to secure by Letters Patent is:

l. A block copolyrner of a polyaminotriazole having a chain length of at least 20 monomeric units and an amine-terminated polyamide, said polyamide having a molecular weight of at least as high as that of the polyaminotriazole, and having the nitrogen atoms of its amide groups linked to aromatic nuclei in the chain by attachment of said nitrogen atoms to carbon atoms, all of whose other valences are satisfied by atoms of the group consisting of carbon and hydrogen.

2. A block copolymer according to claim 1 wherein said polyaminotriazole has an inherent viscosity of at least about 0.33.

3. The method of forming a block copolymer which comprises heating a mixture of a polyaminotriazole having a chain length of at least 20 monomeric units and an amine-terminated polyamide, said polyamide having a molecular weight at least as high as that of the polyaminotriazole and having the nitrogen atoms of its amide groups linked to aromatic muclei in the chain by attachment of said nitrogen atoms to carbon atoms, all of whose other valences are satisfied by atoms of the group consisting of carbon and hydrogen.

4. The method of claim 3 in which said mixture is a pulverized mixture.

5. The method of claim 3 in which said mixture is a solution.

6. The method of claim 3 in which said polyaminotriazole contains the structure wherein n is an integer from 6 to 12.

7. The method of claim 6 wherein n is 8.

8. The method of claim 3 wherein said polyamide is the condensation product of adipic acid with an excess of m-xylylene diamine.

9. The method of claim 3 wherein said polyamide is the condensation product of adipic acid with an excess of p-xylylene diamine.

1G. The method of claim 3 wherein said polyamino triazole has an inherent viscosity of at least about 0.33.

References Cited in the file of this patent UNITED STATES PATENTS 2,193,529 Cofiman Mar. 12, 1940 2,395,642 Prichard Feb. 26, 1946 2,512,627 Fisher et a1. June 27, 1950 

1. A BLOCK COPOLYMER OF A POLYAMINOTRIAZOLE HAVING A CHAIN LENGTH OF A LEAST 20 MONOMERIC UNITS AND AN AMINE-TERMINATED POLYAMIDE, SAID POLYAMIDE HAVING A MOLECULAR WEIGHT OF AT LEAST AS HIGH AS THAT OF THE POLYAMINOTRIAZOLE, AND HAVING THE NITROGEN ATOMS OF ITS AMIDE GROUPS LINKED TO AROMATIC NUCLEI IN THE CHAIN BY ATTACHMENT OF SAID NITROGEN ATOMS TO CARBON ATOMS, ALL OF WHOSE OTHER VALENCES ARE SATISFIED BY ATOMS OF THE GROUP CONSISTING OF CARBON AND HYDROGEN. 